Manganese-base alloy



Patented ay 4, 1943 2,317,979 I MANGANESE-BASE r Reginald S. Dean andClarence T. Anderson, Salt Lake City, Utah, a'ssignors to Chicago Development Company, Chicago, 111., a corporation' of Illinois No Drawing.Application May 14, 1941, Serial No. 393,371

present invention is from 50% to 85%, the nickel content from 2% to 30%and the remainder, not less than 10%, of the alloys comprises at leastone of the elements zinc and copper.

We have also found that the coefficient 01 linear expansion may beincreased and other desirable properties in the alloys enhanced bysubjecting the said alloys to a suitable heat treatment. We have foundthat, for best results, the alloys should be cooled from a temperaturearound 900 degrees 0., the cooling being either slow or rapid. Thepreferable condition of the alloys is obtained by slow cooling. By slowcooling, as used herein, we mean the cooling of the alloys at a ratewhich would be obtained if they were allowed to cool in an ordinaryheat-treating furnace. In general, the cooling rate ShOLllu be such thatat least six hours is required for the alloys to reach room temperatureafter the heat is turned off. It will be understood, of course, that thelength of time required to brin the temperature of the heated alloysdown to room temperature during the slow cooling process will depend, inpart, upon-the size and shape of the alloy elements being treated aswell as upon the exact result desired by way of coefiicient of linearexpansion, modulus of elasticity, fatigue, strength, and otherproperties sought. It will be understood, also, that the cooling may becarried out in air although, for best results, it should be carried. outin an inert atmosphere.

The following are examples of alloys falling within the scope of thepresent invention, all of which have a coefficient of linear expansiongreats: than 20 x 10'- centimeters per centimeter per degree centigradebetween and 100 degrees C. and many of them have substantially greatercoefficients. Thus, for example, the alloy containing 72% manganese, 10%nickel, and 18% of either copper or zinc or substantially equalproportions of copper and zinc, has a coefilcient of linear expansionapproximately centigrade, between 0 and degrees C. The electricalresistance of the alloys varies from about to 200 microhms percentimeter cubed. In general, cold working the alloys lowers thecoeflicient of expansion and this lowering is more pronounced inproportion to the amount of zinc in the alloys. Those of the alloyswhich contain zinc to the exclusion of copper or which containsubstantial proportions of zinc with respect to the amount/of the copperhave the advantage of a lower specific gravity and are somewhat cheaperin cost.

We have indicated hereinabove that the high coefiicients of linearexpansion, coupled with the various other properties of the alloys ofour invention, make the said alloys highly useful for a wide variety ofpurposes, particularly, as bimetal strips for temperature control work.The alloys or the present invention may be utilized as the highexpansion member in combination with any low expansion member such asvarious steels, Invar, and other low expansion members such asdisclosed, for example, in Patents Nos. 1,947,065 and' 1,991,438.definitely preferred low expansion member of our bi-metal strips. Manyof the lei-metallic strips made in accordance with our invention haveabout twice the movement per unit of temperature' change as comparedwith conventional strips such as those consisting of l'nvar with a 5brass havin a relatively high temperature coefilcient of expansion. Inproducing the bimetal strips, they may be welded, fused, brazed orotherwise fabricated in accordance with knownpractices.

Another type of control unit for which the alloys of our invention arewell adapted, is one where the expansion of the material, for example, abar, is utilized for control purposes. Such control members may carry acurrent and may 28 x 210- centimeters per centimeter per degree be usedin a circuit where rise of temperature Invar constitutes the producedthrough resistance of the member causes such linear expansion. of thecontrol member as to open a set of contacts and interrupt the current.In such a system, the member is directly responsive to current input.Other specific installations of this general type may be used. 1 i

In order to produce the most satisfactory alloys for our purposes,wefprefer to employ a high purity manganese in the preparation of thealloys of our invention, that is, a manganese having a purity of atleast about 99.0%. Electrolytic manganese having a purity of theorder of99.9% is especially satisfactory and, therefore, its use represents aparticularly preferred embodiment of our invention. The nickel, copperand zinc should also preferably be highly pure, for the best results,and We prefer to use the electrolytic metals.

While the alloys of our invention are particularly useful in thoseenvironments where high coefficients of linear expansion are desired, itwill be understood that they are not so limited in their use but mayalso be employed for the fabrication of various other elements.

What we claim as new and desire to protect by Letters Patent of theUnited States is:

1. An alloy having a high coeflicient of linear expansion, said alloyconsisting essentially of manganese, nickel and zinc, the manganeseconstituting from 50% to 85%, the nickel from 2% to 30%, balancesubstantially all zinc, the zinc constituting at least of the alloy.

2. An alloy having a high coemcient of linear expansion, said alloyhaving been slow-cooled from about 900 degrees C. and consistingessentially of high purity electrolytic manganese, nickel and zinc, themanganese constituting from 50% to 80%, the nickel from 2% to 30%,balance substantially all zinc, the zinc constituting at least 10% ofthe alloy.

3. An alloy having a high coefficient of linear expansion, said alloyconsisting essentially of manganese, nickel and zinc, the manganeseconstituting at least 50%, the nickel at least 10%, balancesubstantially all zinc, the zinc constituting at least 10% of the alloy.

4. An alloy having a high coefficient of linear expansion, said alloyhaving been slow-cooled from about 900 degrees C. and consistingessentially of manganese, nickel and zinc, the manganese constitutingapproximately 72 the nickel approximately 10%, and the zincapproximately. 18%.

5. An alloy having a high coefllcient of linear expansion, said alloycontaining from to manganese, from 10% to 30% nickel, balancesubstantially all at least one of the elements copper and zinc, the zincconstituting at least 4% of the alloy, the total of said elements addingup to substantially 6. An alloy having a high coeflicient of linearexpansion, said alloy containing about 72% manganese, about 10% nickel,and the balance consisting substantially entirely of the elements copperand zinc, the zinc constituting not less than 4% of said alloy.

7. An alloy having a high coefficient of linear expansion, said alloyconsisting essentially of manganese, nickel and zinc, the manganeseconstituting approximately 72%, the nickel approximately 10%, and thezinc approximately 18%.

8. A control member in the form of a strip which is adapted to expandand contract on heating and cooling, respectively, made of an' alloyconsisting essentially of manganese, nickel and zinc, the manganeseconstituting approximately 72%, the nickel approximately 10%, and thezinc approximately 18% 9. A control member in the form of a strip whichis adapted to expand and contract on heating and cooling, respectively,made of an alloy having a high coeflici nt of linear ;xpansion, saidalloy containing about 72% manganese, about 10% nickel, and the balanceconsisting substantially entirely of the elements copper and zinc,

the zinc constituting not less than 4% of said alloy.

10. An alloy having a high coefficient of linear expansion, said alloyhaving been slow-cooled from about 900 degrees C. and containing about72% manganese, about 10% nickel, and the balance consisting of at leastone of the elements copper and zinc.

' REGINALD S. DEAN.

CLARENCE T. ANDERSON.

